This was an interesting one for a Johnny's Entertainment song. I think there have been tunes done by various Johnny's groups in the past which had a bit of a Mood Kayo twist in it, but for some reason, "Garasu no Shonen" (Glass Boys) struck me as being less pastiche than usual. But then again, when you have Tatsuro Yamashita and Takashi Matsumoto（山下達郎・松本隆）behind its creation, expectations can be high.
And according to the J-Wiki article on the song, head honcho Johnny Kitagawa told Yamashita and Matsumoto regarding what would eventually become the debut tune for the Kinki Kids that he would only accept a million copies in sales AND a debut ranking of No. 1 on Oricon as the minimum levels for success. Even for those guys, I could only imagine that their deodorant was probably working overtime with that commandment from the enigmatic Johnny. The two started raising questions like "If I were (songwriter) Kyohei Tsutumi, what kind of song would I make?" Pressure was indeed on.
Even when "Garasu no Shonen" was completed and released in July 1997, there were criticisms of it being "too old-fogeyish" and "can't dance to it". However, there was the more generous other side which praised the song as being nostalgic to the point that it sounds fresh and which apparently brought attention from people who weren't usually fans of Yamashita or Matsumoto. In fact, crazily enough, both of Johnny's requests were met: it started Oricon life at the No. 1 position and sold over 1.6 million copies! It would finish the year as the No. 2 song, just behind Namie Amuro's（安室奈美絵） massive hit, "Can You Celebrate". I can only think that the Domoto guys probably still send Christmas cards the size of a Toyota to their songwriters.
Listening to "Garasu no Shonen", I had no doubt that it was sung by a Johnny's duo. However there was also that strong echo of yesteryear almost to the point that I could imagine the karaoke video of it having the usual Mood Kayo trope of a couple dancing on the floor and then sipping their glasses of booze at the bar. And this was a song created by a couple of guys who helped pioneer City Pop/New Music in the 1970s.
I don't know when Yamashita did a cover of the song but here it is.